You might not know that the Cricket World Cup is going on right now, and if you do you might not care. But there are about a billion people out there who do care. And to those people, the feat achieved yesterday by West Indies batsman Chris Gayle is a huge deal.

What did Gayle do? He hit the first ever “double century” in the history of the CWC.

That probably means nothing to you, so let me explain. In cricket, as in baseball, the object is to score runs, and to score those runs, a batter (or batsman in cricket) hits a ball and runs back and forth. The difference comes in how the “at-bats” and “innings” are divided up.

In baseball, your at-bat is over when you either get a hit or make an out. In cricket, your at-bat is over when you make an out, but not when you get a hit. You get to keep batting until they get you out. So if you’re really good, you can just keep going and going, racking up tons of runs.

A “century” is therefore when you score one hundred runs in a single at-bat. A “double century” is when you score 200.

Double centuries are extremely rare in One-Day International (or ODI) cricket, the form of cricket played at major international competitions like the Cricket World Cup. Until yesterday, when Chris Gayle scored 215 runs, there had only been four, and none of them came in the game’s most prestigious competition.

To put this baseball terms, batting for a double century in cricket is like recording 10 RBI in a single game, something only 13 players in the history of baseball have accomplished.